﻿using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace SuperiorCommon
{
    public class SecretClass
    {
        private static string _QueryStringKey = "fhd61222"; //URL传输参数加密Key 
        /// <summary>
        /// 加密URL传输的字符串
        /// </summary>
        /// <param name="QueryString"></param>
        /// <returns></returns>
        public static string EncryptQueryString(string QueryString)
        {
            return Encrypt(QueryString, _QueryStringKey);
        }

        /// <summary>
        /// 解密URL传输的字符串
        /// </summary>
        /// <param name="QueryString"></param>
        /// <returns></returns>
        public static string DecryptQueryString(string QueryString)
        {
            string deskey = Decrypt(QueryString, _QueryStringKey);
            return Decrypt(QueryString, _QueryStringKey);
        }

        private static string Decrypt(string pToDecrypt, string sKey)
        {
            try
            {
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();

                byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
                for (int x = 0; x < pToDecrypt.Length / 2; x++)
                {
                    int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                    inputByteArray[x] = (byte)i;
                }

                des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);  //建立加密对象的密钥和偏移量，此值重要，不能修改   
                des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();

                StringBuilder ret = new StringBuilder();  //建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象   

                return System.Text.Encoding.Default.GetString(ms.ToArray());
            }
            catch
            {
                return "error1001";
            }
        }

        private static string Encrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();  //把字符串放到byte数组中   

            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            //byte[]  inputByteArray=Encoding.Unicode.GetBytes(pToEncrypt);   

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);  //建立加密对象的密钥和偏移量 
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);   //原文使用ASCIIEncoding.ASCII方法的GetBytes方法  
            MemoryStream ms = new MemoryStream();     //使得输入密码必须输入英文文本 
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }
    }
}
